Fix yaml syntax error when use multilines in dns_etchosts (#6960)

roles/kubernetes-apps/ansible/templates/coredns-config.yml.j2

@@ -65,5 +65,5 @@ data:
     }
 {% if dns_etchosts | default(None) %}
   hosts: |
-   {{ dns_etchosts }}
+    {{ dns_etchosts | indent(width=4, indentfirst=None) }}
 {% endif %}

roles/kubernetes-apps/ansible/templates/nodelocaldns-config.yml.j2

@@ -85,5 +85,5 @@ data:
     }
 {% if dns_etchosts | default(None) %}
   hosts: |
-   {{ dns_etchosts }}
+    {{ dns_etchosts | indent(width=4, indentfirst=None) }}
 {% endif %}